Sunitinib and its salts are antineoplastic agents, which were disclosed in WO Patent Publication No. 01/60814 and U.S. Pat. No. 6,573,293. Sunitinib is known by the chemical name N-[2-(diethylamino)ethyl]-5-[(Z)-(5-fluoro-1,2-dihydro-2-oxo-3H-indol-3-ylidene)methyl]-2,4-dimethyl-1H-pyrrole-3-carboxamide. Sunitinib is represented by the following structure.

Polymorphism is defined as “the ability of a substance to exist as two or more crystalline phases that have different arrangement and/or conformations of the molecules in the crystal Lattice. Thus, in the strict sense, polymorphs are different crystalline forms of the same pure substance in which the molecules have different arrangements and/or different configurations of the molecules”. Different polymorphs may differ in their physical properties such as melting point, solubility, X-ray diffraction patterns, etc. Although those differences disappear once the compound is dissolved, they can appreciably influence pharmaceutically relevant properties of the solid form, such as handling properties, dissolution rate and stability. Such properties can significantly influence the processing, shelf life, and commercial acceptance of a polymorph. It is therefore important to investigate all solid forms of a drug, including all polymorphic forms, and to determine the stability, dissolution and flow properties of each polymorphic form. Polymorphic forms of a compound can be distinguished in the laboratory by analytical methods such as X-ray diffraction (XRD), Differential Scanning calorimetry (DSC) and Infrared spectrometry (IR).
U.S. Patent Application No. 2003/0069298 disclosed two crystal forms, Form I (characterized by an x-ray powder diffraction patterns having peaks expressed as 20 at 13.2, 19.4, 24.2 and 25.5 degrees) and Form II (characterized by an x-ray powder diffraction patterns having peaks expressed as 20 at 3.0, 12.1, 14.5 and 27.7 degrees) of sunitinib malate.
One object of the present invention is to provide a novel crystalline form of sunitinib malate and a process for preparing it.
According to another object of the present invention is to provide process for preparing crystal form I of sunitinib malate.
Still another object of the present invention is to provide pharmaceutical compositions containing the novel crystalline form of sunitinib malate.